Zimbra Server to Server Migration - Large folders are split up for every 1000 emails

Hi,

We are a new network edition customer with about 10000 mailboxes. We are migrating some accounts from a Zimbra 8 test server into our multi-server environment. When exporting the accounts, we notice that for large mailboxes, folders that have over a 1000 emails are split into several folders of 1000 emails each, and named !1, !2, etc. For example, if there are 3500 emails in Inbox, the export file contains four folders with the following names: Inbox, Inbox!1, Inbox!2 and Inbox!3.

We were hoping that when importing the files back in, the emails would all be merged back into one folder again, but this doesn't seem to happen. Instead, the folder structure is retained, and this is very annoying to our users, as this structure is then replicated to Zimbra Desktop, Outlook, iPhones, etc.

We couldn't find any information in the documentation explaining this behaviour, and if there was some way of turning it off. Presently, our only solution seems to be to write a script to parse and put everything back into the right folder, and we really do not want to do this. We using zmmailbox to do the import/export are following the procedure outlined in this blog post on server to server migrations.